1. Field of the Invention
The present invention relates to an endoscope utilizing a solid state imaging device, and more particularly to an endoscope wherein the standstill control of an image of a monitor television set and the shutter operation of a camera are effected by a single control button provided on a control section of the endoscope.
2. Description of the Prior Art
Recently, there has been proposed an endoscope of a novel type, wherein a solid state imaging device such as an image sensor of a charge coupled device (CCD) type or a metal oxide silicon (MOS) type is provided in the forward end of an insertion section of the endoscope, and a video signal of an object of interest obtained from this solid state imaging device is displayed on a screen of a monitor television set or the like through a control unit, so that the object of interest can be observed. In the above-described endoscope of the novel type, differing from a conventional endoscope which has been adapted to directly observe an image transmitted by an optical fiber bundle through an eyepiece section, the image of interest is observed on the screen of the television set and the like, so that such advantages can be offered that the eyepiece section can be dispensed with and the control section can be handled in an easy posture.
FIG. 1 shows an outline of the arrangement of the endoscope of this novel type.
In FIG. 1, designated at 10 is a generally pistol-shaped control section, 12 a control unit provided with various control mechanisms including a light source, and 14 a monitor television set. The control section is constituted by a grip portion 10A, a button 10B for suction and air-water supply and an angle control knob 10C. Connected to the forward portion of the control section 10 is an insertion section 16 operable in a very deep portion of a living body or the like. Connected to the bottom portion of the grip portion 10A of the control section 10 is one end of a connector section 18, the other end of which is bifurcated. A plug 20 and a connector 22 are provided on the bifurcated end portions, respectively. The plug 20 is provided with a light guide rod 24, a terminal pin for controlling a value for air and water supply, being interlocked with the control button 10B of the control section 10, a tube connected to an air supply pump in the control unit 12 and the like. The plug 20 is connected to a socket 26 of the control unit 12. Furthermore, the connector 22, being connected to a socket 28, outputs a driving signal from the control unit 12 to a solid state imaging device incorporated in the forward end of the insertion section 16 and inputs a video signal from the solid state imaging device to the control unit 12.
As shown in FIG. 2, the control unit 12 is constituted by:
a light quantity control section 32 for manually adjusting a quantity of light from a light source 30;
a rotary color filter 38 provided on a disc thereof with filters of three colors including R(red), G(green), and B(blue) and arranged at intervals of every 120.degree. or 1/3n (n is an integer), having a function of successively changing a light from the light source 30 into colors including R, G and B and supplying the same to a light guide 34, and rotatably driven by a motor 36;
a video signal processing section 42 for feeding a driving signal S s to a solid state imaging device 40 in the forward end of the insertion section, synchronizing image pickup signals Sv from the solid state imaging device 40 with color changeover timings of the rotary color filter to obtain color sequential signals including R, G and B, and outputting separation signals including R, G and B;
a control section 44 for controlling a valve and the like interlocked with the control button 10B of the control section 10; and
a power source section 46 for feeding electric power to the video signal processing section 42.
The video signal processing section 42 is constituted by:
an image processor 50 for delivering R, G and B image signals successively outputted from the solid state imaging device 40 in synchronism with the rotation of the motor 36, i.e. the rotation of the rotary color filter 32 to memories of respective color signals;
an analogue-digital (A/D) converter 52 for converting an analogue color signal outputted from the processor 50 into a digital color signal;
a R signal memory 54a, a G signal memory 54b and a B signal memory 54c for storing R, G and B signals successively outputted from the converter 52;
digital-analogue (D/A) converters 56a.about.56c connected to memories 54a.about.54c, for converting image signals outputted from the respective memories into analogue signals; and
an output processor 58 for reading R, G and B signals outputted from these D/A converters 56a.about.56c, composing the same to provide a color image, converting the color image into NTSC (National television system committee) signals or signals or the like and outputting the same. Additionally, when a standstill signal SH is applied from a terminal 60 to the output processor 58, the output processor 58 stops the readout from the memories 54a.about.54c, prevents the write-in of buffer memories in the output processor 58, and repeatedly performs only the read-out, so that the image display on the monitor television set 14 can be stopped.
Furthermore, the production of monochromatic lights of R, G and B has been made by use of the filter 38, however, light sources producing three primary colors, respectively, may be used.
Description will hereunder be given of action of the endoscope with the above-described arrangement. In the first place, an operator inserts the plug 20 into the socket 26 of the control unit 12 and connector 22 into the socket 28 of the control unit. The operator turns on power source switches of the control unit 12 and the monitor television set 14, adjusts the lamp light quantity control section 32 (an adjusting knob is provided on a panel face of the control unit 12), and directs the lights of red, green and blue successively emitted from a lens provided on an emitting end of the light guide through the light guide inserted into the endoscope. Subsequently, the operator grasps the control section 10 and inserts the forward end of the insertion section 16 little by little to the position of the object of interest, watching the image displayed on the monitor television 14. After the forward end of the insertion section 16 is set at a desirable position, subsequently, the control knob 10c is rotated and the forward end portion of the insertion section is directed to the position of observation, while the monitor television set 14 is being observed. Furthermore, the control button 10B is operated by an index finger as necessary, to perform a water supply operation, an air supply operation or a suction operation. Further, when necessary, a forceps or the like is inserted through an insertion hole, not shown, of the control section 10, whereby a piece of flesh in an affected portion may be picked and so forth.
An image of an affected portion is picked up by the solid state imaging device 40 through a lens incorporated in the forward end portion of the insertion section 16, photoelectro-transducing signals thereof are successively outputted in the order R.fwdarw.G.fwdarw.B, and successively stored in the memories 54a.about.54c for exclusive uses by every color components through the image processor 50 and the A/D converter 52. Upon completion of storing of one picture, image data of three colors are read out of the memories 54a.about.54c through the D/A converters 56a.about.56c, and outputted to the output processor 58. The output processor 58 composes R, G and B signals to produce a color picture, further, applies a predetermined process thereto so that the picture can be seen on the ordinary monitor television set, and the picture is outputted.
Now, as the mode of use of the endoscope, there are many cases where the operator tries to grasp the conditions of an affected portion, while observing an image on the screen of the monitor television set, and the images frequently need to be recorded and preserved. As a measure of recording, the picture thus monitored is photographed by a still camera.
In this case, in order to photograph the image displayed on the monitor television set stably and clearly, it is desirable to make the monitored image stand still, and thereafter, to release the shutter of the camera. However, when the control section 10 of the endoscope is provided with two buttons for making the image stand still and for releasing the shutter of the camera, if photographing by use of the camera is performed, then the two buttons should be operated separately of each other, thus presenting the disadvantages that it is troublesome to operate the buttons separately of each other and quick operations cannot be performed.